155 resultados para Image processing - Digital techniques
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Techniques of image combination, with extraction of objects to set a final scene, are very used in applications from photos montages to cinematographic productions. These techniques are called digital matting. With them is possible to decrease the cost of productions, because it is not necessary for the actor to be filmed in the location where the final scene occurs. This feature also favors its use in programs made to digital television, which demands a high quality image. Many digital matting algorithms use markings done on the images, to demarcate what is the foreground, the background and the uncertainty areas. This marking is called trimap, which is a triple map containing these three informations. The trimap is done, typically, from manual markings. In this project, methods were created that can be used in digital matting algorithms, with restriction of time and without human interaction, that is, the creation of an algorithm that generates the trimap automatically. This last one can be generated from the difference between a color of an arbitrary background and the foreground, or by using a depth map. It was also created a matting method, based on the Geodesic Matting (BAI; SAPIRO, 2009), which has an inferior processing time then the original one. Aiming to improve the performance of the applications that generates the trimap and of the algorithms that generates the alphamap (map that associates a value to the transparency of each pixel of the image), allowing its use in applications with time restrictions, it was used the CUDA architecture. Taking advantage, this way, of the computational power and the features of the GPGPU, which is massively parallel
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Pós-graduação em Engenharia Elétrica - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The article discusses a proposal of displacement measurement using a unique digital camera aiming at to exploit its feasibility for Modal Analysis applications. The proposal discusses a non-contact measuring approach able to measure multiple points simultaneously by using a unique digital camera. A modal analysis of a reduced scale lab building structure based only at the responses of the structure measured with the camera is presented. It focuses at the feasibility of using a simple ordinary camera for performing the output only modal analysis of structures and its advantage. The modal parameters of the structure are estimated from the camera data and also by using ordinary experimental modal analysis based on the Frequency Response Function (FRF) obtained by using the usual sensors like accelerometer and force cell. The comparison of the both analysis showed that the technique is promising noncontact measuring tool relatively simple and effective to be used in structural modal analysis
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Given the widespread use of computers, the visual pattern recognition task has been automated in order to address the huge amount of available digital images. Many applications use image processing techniques as well as feature extraction and visual pattern recognition algorithms in order to identify people, to make the disease diagnosis process easier, to classify objects, etc. based on digital images. Among the features that can be extracted and analyzed from images is the shape of objects or regions. In some cases, shape is the unique feature that can be extracted with a relatively high accuracy from the image. In this work we present some of most important shape analysis methods and compare their performance when applied on three well-known shape image databases. Finally, we propose the development of a new shape descriptor based on the Hough Transform.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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A method has been developed to obtain quantitative information about grain size and shape from fractured surfaces of ceramic materials. One elaborated a routine to split intergranular and transgranular grains facets of ceramic fracture surfaces by digital image processing. A commercial ceramic (ALCOA A-16, Al2O3-1.5% of CrO) was used to test the proposed method. Microstructural measurements of grain shape and size taken from fracture surfaces have been compared through descriptive statistics of distributions, with the corresponding measurements from polished and etched surfaces. The agreement between results, with the expected bias on grain size values from fractures, obtained for both types of surfaces allowed to infer that this new technique can be used to extract the relevant microstructural information from fractured surfaces, thus minimising the time consuming steps of sample preparation. (C) 2003 Elsevier Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Digital image processing is a field that demands great processing capacity. As such it becomes relevant to implement software that is based on the distribution of the processing into several nodes divided by computers belonging to the same network. Specifically discussed in this work are distributed algorithms of compression and expansion of images using the discrete cosine transform. The results show that the savings in processing time obtained due to the parallel algorithms in comparison to its sequential equivalents is a function that depends on the resolution of the image and the complexity of the involved calculation; that is efficiency is greater the longer the processing period is in terms of the time involved for the communication between the network points.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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OBJETIVO: Avaliar a posição do supercílio em diferentes idades, utilizando medidas angulares. MÉTODOS: Foram avaliados indivíduos com idade de 4 a 6 anos (Grupo de crianças) e igual ou superior a 50 anos (Grupo de idosos), separados em faixas etárias, avaliando-se a posição do supercílio por meio de imagens digitais, utilizando medidas angulares. As imagens foram tomadas em posição primária do olhar, utilizando filmadora Sony Lithium, e posteriormente transferidas para computador MacIntosh G4 e processadas pelo programa NIH 1,58. Os parâmetros analisados foram: ângulo interno, externo e vertical da cauda do supercílio. As comparações foram entre sexos, faixas etárias e lateralidade. Os resultados obtidos foram submetidos à análise estatística. RESULTADOS: A comparação das medidas angulares mostrou que houve diferença significativa na posição da cauda do supercílio entre os grupos estudados quando comparados dentro do grupo com faixa etária semelhante. Porém, comparando-se crianças e adultos, houve diferença em todos os tipos de ângulos estudados. CONCLUSÕES: A posição do supercílio avaliada por medidas angulares mostrou diferenças entre crianças e idosos, revelando associação positiva com a idade.